Inj timing, transients

4.8 single turbo, 209/217 cam : Hey guys take a look when u get a chance. I've attached a log of crank and idle. The truck fires right up but is a little lean right after startup. then later in the log you can see me rev the motor i expect some delay to the O2 sensor, but after the initial lean, then its rich, AND THEN its way lean for a bit AND THEN its rich and tampers back toward lambda. Can i remedy this somehow? Would this be something to do with the injectors or in the transients? Oh the injectors are from FIC 52lb, and i entered all the data that came with them.

Your MAP data looks wrong. The KPA before the engine even started was maxed at 105KPA, it should read 100KPA at sea level and you are logging the wrong channel if it stops at 105kpa. Remove the 1 bar channel and replace it with the 2 bar.

I wouldn't set the entire open loop eq ratio table to 1.00, engines don't exactly like to run at stoich when they are cold. That's why the factor settings have it run around 12 to 13 AFR and slowly work it's way towards stoich above 120 degree coolant temp and higher injector tip temp.

Fix your base idle advanced, it's got some weird dips in it. Make sure the base idle timing matches the same spots on the other high/low timing tables, that when it switches from idle timing to "normal" timing there isn't such a huge jump.

I don't have the injector data in front of me but double check the min injector pulse. It is suppose to be .023 or .230??

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Originally Posted by 5FDP

I don't have the injector data in front of me but double check the min injector pulse. It is suppose to be .023 or .230??

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I was looking at that too, definitely weird...then something else caught my eye. And turns out he says he has a walbro 450 in there on the stock FSCM.

OP, before you do anything else, the fuel system needs attention. You are running a fuel pump the CL control in the FSCM was never meant for, and there aren't enough cals available to tune that control loop. Unless you want to run a regulator, the only bandaid available is hacking up what's available to prevent all of those constant pressure drops which are going to make fueling unstable.

1) Set all of your desired pressures to the same value. IFR clip happens at 432, so target 380kpa for all settings.

2) Set FP min DC to a higher value. Min DC is at 10% now...try 40% or so. That big pump is responding slower when fuel demand goes up, so you're getting pressure drops and oscillation while the uncalibrated system tries to respond. Tweak that min DC so that its as high as possible without causing fuel pressure to hang above 380kpa too long when you tip out of the throttle.

3) Set the IFR vs IAT mult table to 1 across the board...those values make no sense and are probably causing hell below 70F.

4) Carry extra fuel pump fuses. Higher min DC will stabilize fuel pressure, but it may pop a fuse. I'm not even sure the FSCM driver will be able to handle it at high load...so that's a risk you're taking. Good luck.

thanks for proofing my tune. i live in the middle of nowhere and noone else around here that i know of is into this stuff. the closest pro tuner is about an hour away and he won't help. in fact he said if i paid him 600 he would start from scratch. after a year and half i'm so close and have learned alot. i aint giving up. anyway i did as you suggested 5F, i corrected the MAP, entered the correct INJ data back in, i had changed it trying to figure out something and forgot. same for the idle timing, i honestly don't remember why i did that. Smoke, i haven't messed with the FSCM since i initially looked at it when i put the walboro in. i may do that later, but i feel i should be able to fix it with the transients. its in the settings. even with stock settings i see different responses to pedal at different IVTs. did that make sense? ive attached the latest and its working! what concerned me this morn is that actual afr isn't what is commanded and the longer it idled the LEANER the ecm was commanding wtf? Is it the ECT multiplier(air) or is it the changes i made in the transients, (i stayed out of the idle areas) BTW im using the ITT for the lean after start i was having.

geneass, how did you install the Walbro 450? I played around with one in a stock Delphi SUV fuel bucket, and tee'd into the pump output to feed the venturi. Have not installed it in the truck, but did some bench testing with a DC PWM motor driver and the pump in a bucket of fuel. With the pump dead-headed, I could not get the pump to run below around 38% duty cycle @ 12v, or 28% @ 15v. Anything below that and it acted like it was sucking air or cavitating, the pump rpm would race and the fuel pressure would drop. Odd, as I ran it plenty to ensure the air was out of my test rig, and it had no problem when maxing it out with no backpressure, or dead-headed (minus what was going out the venturi). Below are my results, with the lb/hr numbers done with the stopwatch on my phone measuring the amount of time to fill a gallon jug while restricting the output to hit the desired pressure (only tested at 3 points). Then the duty cycle it took at various pressure readings while dead-headed, which I planned to use for the Min DC chart and then extrapolate for the missing areas to get in the ballpark.

You have to use 1 credit to license the FPCM if you haven't already.

Attachment 107814

Now that I think about that experiment again, I think 35-38% duty cycle and below was where there were problems, no matter the load(pressure) against the output. I may have just guesstimated in the chart above at 15V/200kpa as a starting point for if/when I put it in the truck and change the FPCM settings.

Also, I never saw it go over 20A current, as fed from a power supply.

Notsure, to be honest I just installed it and entered the FIC injector data and ran it. I haven't noticed any fueling issues, but i'm not a pro. at idle I do see a little fluctuation in fuel pressure 3-4kpa. BUT I got a new one for yall. On this gen 4 what are your thought on nullifying the IVT, ITT and biasing tables and just use IAT for fueling? Has anyone done this/ are you happy with it? I'm trying to get this SD tune perfected but it seems I 'm always making adjustments. I may be too much of a perfectionist and really don't know what an SD tunes's limits are. Thoughts? Advice?

this is an example of what i'm trying to perfect. while idling I can push the skinny pedal and I get a lean spike followed by rich spot. the severity of the spikes get less as IVT rises, so I should be able to tune this out with transients, Right? if you look at my fuel pressure during the pedal inputs it does change, is the pressure drop the problem? I have adjusted the transients some but wanted to ask before I go to far. Also when you guys dump the wastegate exhaust(turbo'd) to atmosphere do you still target 11.8 afr even tho your not measuring the dumped exhaust with the o2. I'm trying to get done with this truck.:burnout:

it might help if I left a log:doh:

DONT zero out IVT, ITT tables! You need them for cold start and hot start. Don't mess with transients until you get your VE completely dialed in.

What MAP are you using? Are you sure you have the right linear and offset for the one you have installed?

I am not sure what PE TPS is that you are logging, others probably know. But it never goes over about 2.5%. Is that all the throttle you gave it on the last log?

Have you bypassed the FPCM, using a return style system? If you are still using the FPCM and you have that Walbro pump, IMO you really need to license it as there is more to do than what is on your Fuel Pump tab. Then, monitoring desired and actual pressure, pump duty cycle, etc, you might be able to get it under control. Like I said above, my Walbro experiment has not made it into the truck yet so I don't know how that is going to go, lol.

Well I thought I was at the final steps on this tune. Just trying to find tune. Pe tps is power enrichment throttle position sensor that's how it log pedal position. I was in the garage logging startup and idle and was just tapping the pedal to see the transients as the IVT temp went up. I'll take a look at the fuel control module and see what's there. Smoke mentioned that too